1. Field of the Invention
This invention relates generally to apparatus for magnetically treating a liquid flowing through a pipe, and pertains more particularly to apparatus that can be readily held in place against the exterior of a magnetic pipe.
2. Description of the Prior Art
Perhaps U.S. Pat. Nos. 4,367,143; 5,078,870; and 5,198,106 are representative of the state-of-the-art. However, as mentioned in the aforementioned issued patents, U.S. Pat. No. 3,228,878 also is representative of earlier prior art. The disclosures of each of these patents mention scale and paraffin problems, pointing out that scale can take various forms but typical of the substances creating scale problems are calcium carbonate, calcium sulfate, barium sulfate, sodium chloride, magnesium sulfate, silica, as well as various oils, waxes and greases in addition to paraffin. Accumulations of these substances on the interior of the pipe obviously produce problems, especially as far as causing a greater resistance to liquid flow within the pipe, and also where heat is applied to the pipe's exterior, the collected substances act as an objectionable thermal insulator. Sufficient accumulations, quite obviously, require that the piping system be inactivated and the pipes individually cleaned out, a time-consuming and costly procedure where the system is an industrial one, particularly due to the fact that the particular piping system is not productive during the shutdown period.
The polarization of diamagnetic materials through the agency of relatively strong magnetic fields provided by permanent magnetic means is generally well understood and need not be repeated at this time, although reference may be made to the patents herein referred to for a basic understanding of what is involved. Very succinctly, however, the principle behind the polarization is to prevent the formation of sufficiently objectionable deposits on the inside of the pipe, with the magnetic action causing the diamagnetic materials to move inwardly under the influence of a sufficiently strong magnetic field.
The difficulty in the past, however, has been with respect to providing sufficiently strong magnetic fields in pipes formed of magnetic material. Particularly, in non-magnetic pipe installations, magnetic flux is easily transferred through the pipe due to the minimum resistance to flux flow through the wall of the pipe and into the liquid flowing through the pipe. However, for magnetic pipes, magnetic flux flow occurs in the wall of the pipe itself such that flux flow through the wall of the pipe and into the liquid flowing through the pipe is substantially reduced. Thus, for magnetic pipe installations, it is currently recommended that a short piece of non-magnetic pipe be inserted in the system and the magnetic units placed upon this piece of non-magnetic pipe. However, the costs associated with the insertion of such non-magnetic pipe pieces and the required stoppage of liquid flow during such insertion are large, especially for systems which operate 24 hours a day without interruption.